Voltage spikes can occur in electrical apparatus. In computers, voltage spikes can be caused by hardware or software. Testing for the cause of voltage spikes is not a simple task, as a spike can result from reflection due to the connection of an unmatched load from the device under test ("DUT") or the pin under test ("PUT") to the tester. Oscilloscopes, storage scopes, and logic analyzers have been used to detect voltage spikes produced during circuit tests.
One problem with oscilloscopes is that they display a waveform of the signal in real time. Since voltage spikes are of short duration, it is not feasible to visually detect them. Further, voltage spikes may go undetected due to lack of sensitivity of the oscilloscope or lack of diligence of the operator. Also, it is often difficult to determine the cause of the voltage spike with an oscilloscope.
Storage scopes are expensive, and require triggering at the proper time so that the spike is captured during the storage time. Improved storage scopes digitize the data and record the digitized signal in memory for later readout, but such devices are often prohibitively expensive. Another problem with digital storage scopes is that low signal resolution render short duration spikes undetectable.
Logic analyzers are also not altogether suitable for voltage spike detection, the principal disadvantage being that the maximum differential voltages which can be measured are too small for many applications.
There is a need for an economical voltage spike detector device which can be attached to the device under test during the entire test period of testing and which can handle a wide range of voltage differentials. There is also a need for an economical voltage spike detector which can detect a spike regardless of signal resolution or operator error.